1. Field of the Invention
The present invention relates to a vehicle headlight device installed into a vehicle to illuminate a front area of the vehicle and, more particularly, a vehicle headlight device using a bulb for emitting visible light and a bulb for emitting an infrared ray as a light source.
2. Background Art
As the vehicle headlight device, for example, such a device has been proposed that the halogen lamp for emitting an upper beam of visible light is employed as the high-beam light source. An infrared ray forming globe for shielding the visible light and transmitting infrared rays only is arranged movably with respect to the high-beam light source. The use of the upper beam and the infrared ray is switched by selecting one of a mode in which the infrared ray forming globe covers the high-beam light source, and a mode in which the infrared ray forming globe is moved ahead of the high-beam light source and the situation located ahead of the vehicle is shot with a CCD (“charge coupled device”) camera and displayed on a display (see Patent Literature 1).
According to the vehicle headlight device of this type, when the illumination light is switched from the upper beam to the infrared ray, the image picked up by the infrared ray CCD camera can be displayed on the display. Therefore, even when the front situation cannot be sufficiently grasped by the low-beam illumination, the situation in front of the vehicle can be sufficiently grasped from the image on the display.    [Patent Literature 1] JP-A-2002-316578 (see p. 3 to p. 5, FIG. 1 to FIG. 3)